In his first appearance before Legco as Acting Chief Executive, Tsang left many questions unanswered over the thorny issue of how to handle the transfer of power to a new chief executive.

The one thing the government is certain of, at least so far, is that the next chief executive's term will be just two years.

Despite warnings that the two-year tenure is vulnerable to legal challenge in the form of a judicial review, Tsang insisted he did not want to resolve the dispute through another Basic Law interpretation.

He warned those who might launch a judicial challenge to take into account the interests of Hong Kong.

"My first priority is to ensure the next chief executive can be elected on July 10 without any hiccups,'' he said. Independent lawmaker Albert Chan declared his intention to take the government to court once it has completed the amendment to the Chief Executive Elections Ordinance in June while Audrey Eu, of the Article 45 Concern Group, said the government should not "distort'' the Basic Law for the sake of political expediency.

Tsang reiterated that he cannot stop any Hong Kong citizen from challenging the government's decision.

``I believe that the Hong Kong courts will not allow this case to drag on indefinitely,'' Tsang said. ``I trust that the local courts will see the urgency of this case and give it first priority.''

The last time the government tried to rush a case through the courts, in the challenge to the Link Real Estate Investment Trust late last year, it was rebuffed and the case is still pending.

Other issues also remain.

If the next chief executive just fills out the remainder of Tung's abandoned term, does that mean his successor - presumably Tsang - could serve two full terms beyond that for a total of 12 years? What if there is another early departure of a chief executive before 2007?

Speaking at a special session of the Legislative Council's House Committee Tsang, justice chief Elsie Leung and constitutional affairs boss Stephen Lam, had no answer for lawmakers on either question Tuesday.

``We know there is a vacuum period between the term of the current Election Committee and the second term of the chief executive. There will be no problem if between July this year and July 2007, there aren't any other chief executive elections,'' Leung said.

Lam said he is aware of the problems and would study the issues with the central government.

``The issue surrounding this vacuum period cannot be resolved by the SAR government alone,'' he said.

Tsang said his adminstration is determined to overcome any obstacle to ensure that Tung's successor will be elected on July 10, shortly before the current 800-strong Election Committee is dissolved, to serve out the remaining two-year term left by Tung.

Leung pointed out that under Basic Law the term of office of the current Election Committee is five years and it is responsible for electing a chief executive until 2007. Hong Kong is divided on the length of office of Tung Chee-hwa's mid-term replacement since the Basic Law stipulates the length of the chief executive's term shall be five years and that he or she may serve for not more than two consecutive terms.

Tsang defended the decision to support Beijing's call for a two-year term for the next chief executive. After Leung consulted mainland Basic Law drafters, Tsang said, they agreed that the partial term should be two years, in line with both the ``original intent'' of the drafters and ``mainland practice.''

Lawmaker Albert Cheng hit out at Leung, saying: ``If your principle is valid, since Tung was elected by this Election Committee, it means it will elect another Tung and his policies cannot be overturned by his successor. Then what's the point of Tung's departure? How about we retain Tung who has stirred up fierce public discontent?'' he said.

Tsang also said he is still undecided about whether to run as chief executive, but that if he does, he will resign from the post of Chief Secretary for Administration before June 5, and Financial Secretary Henry Tang will take over as acting chief executive during the election period.