TEHRAN (Reuters) - The Iranian government has cracked down on political activists, jailed journalists and pursued policies that have hurt the poor despite its populist slogans, an Iranian rights group said on Monday.

The Defenders of Human Rights Centre, a group led by 2003 Nobel Peace Laureate Shirin Ebadi, called on government to "respect the nation's rights" to strengthen its "social base".

The group, which issued a similarly outspoken report in July, cited examples of what it said were abuses such as detentions of students and journalists, as well as people sentenced to death for crimes committed before they were 18.

"It is painful to say that the ... government, despite its populist slogans, has further limited the space for political, unionist, press and student activists," the group said in the report faxed to Reuters.

Western diplomats and rights groups have said the government of President Mahmoud Ahmadinejad has clamped down on dissent, which some say may partly be a response to mounting Western pressure over Iran's nuclear programme.

The United States and its Western allies are pushing for a third round of U.N. sanctions on Iran for failing to heed U.N. demands to halt nuclear work the West fears is being used to build atomic bombs. Tehran denies the charge.

The Iranian government denies rights abuses, saying it supports free speech and welcomes constructive criticism. It also says the judiciary acts independently in upholding the law.

The rights group blamed the government for inflation that was hurting the poor most. Ahmadinejad secured votes of many of the country's poorest in the 2005 presidential election by vowing to share out Iran's oil wealth fairly.

"The heavy burden of the rising prices, especially in the housing market, has taken a remarkable number of people under the poverty line and deprived them from having the minimum (standard for a) dignified life," it said.

Government officials defend their economic policies and say inflation, officially put at about 18 percent, is under control.

The report said the press was facing growing "pressure" and referred to detained journalists such as Asso Saleh, a Kurd on the editorial board of a Kurdish weekly in Iran who the group said was jailed for a year for "distributing false information".

It also said that student activists had been detained and suspended from their studies, while university professors had been dismissed from their posts.

Students were once at the vanguard of the reform movement in Iran but in recent years have lost much of their voice, which students partly blame on the crackdown.

(Editing by Edmund Blair)