Mr Haniya spoke on the issue with European lawmakers

Mr Johnston was seized at gunpoint in Gaza on 12 March.

Mr Haniya, of Hamas, said it was important to the Palestinian government that the journalist was freed and able to resume his work.

UN Secretary General Ban Ki-moon has repeated his call for Mr Johnston to be released immediately.

There has been no direct information on the correspondent's fate since he was seized after leaving his office in Gaza City.

Awards tribute

Mr Haniya was speaking after meeting members of the European parliament who are visiting Gaza.

The head of the European delegation said they had raised the issue with Mr Haniya.

Mr Johnston's image was projected on BBC Television Centre Monday

Last week, the European parliament called on the Palestinian government to do everything possible to secure Mr Johnston's release.

Palestinian Deputy Prime Minister Azzam al-Ahmad has said again that the information he has is that Mr Johnston is "in good health".

The UN secretary general, speaking in New York, said he wanted "to take this opportunity to plead for the immediate release of the BBC journalist Alan Johnston, abducted in Gaza".

On Monday evening, an image of Mr Johnston's face was projected on the outside wall of BBC Television Centre in west London.

Also on Monday, a minute's silence was held at the UK's main radio awards ceremony, the Sony awards, to highlight the demand to free Mr Johnston.

BBC radio presenter John Humphrys, who received an award, paid tribute, saying Mr Johnston deserved it more.

Mr Johnston joined the BBC World Service in 1991 and has spent eight of the last 16 years as a correspondent, including periods in Uzbekistan and Afghanistan.

He has lived and worked in Gaza for three years and was the only Western reporter permanently based in the often violent and lawless territory.