BUENOS AIRES (Reuters) – Former Argentine President  Nestor Kirchner will run for a seat in Congress in a bid to  bolster the left-leaning ruling party in June 28 mid-term  elections, a leading government official said yesterday.

Kirchner heads the Peronist party but is widely seen as  unofficially running the government alongside his wife,  President Cristina Fernandez, whose popularity has sunk due to  economic woes and a prolonged tax war with farmers.

Kirchner will head a list of congressional candidates from  his party in the major electoral battleground of Buenos Aires  province, the region’s governor, Daniel Scioli, said.

Fernandez supporters hope his candidacy will strengthen the  pro-government list of candidates running under Argentina’s  proportional representation system and help the Argentine  leader keep her congressional majority.

A weak showing, analysts say, will leave his wife’s  centre-left government and the couple’s political clout  significantly weakened.

Political uncertainty has heightened in Argentina ahead of  the vote because of concerns that Fernandez will be unable to  govern effectively if her allies fare poorly.

Half of the 256-seat lower house and one third of 72  senators will be elected next month, and some opinion polls  show Fernandez likely to lose her majority in the legislature.

In recent public appearances, Kirchner warned voters that  if they did not support the ruling party Argentina could return  to the political and economic chaos of 2001-2002, when bank  deposits were frozen and the currency was devalued.

The opposition has accused Fernandez of moving ahead the  election, originally scheduled for October, so that it would  occur before an economic slowdown linked to the global  recession eroded support for her government.

Kirchner enjoyed high approval ratings during his 2003-2007  term in office, when he oversaw an economic rebound. There is  speculation that he will seek the presidency again when his  wife’s term ends in 2011.

Fernandez has battled high inflation, a tax revolt by farmers,  a looming debt financing crunch and complaints of high crime.

Argentine political analyst Rosendo Fraga said the  political showdown with farmers was expected to cost the  government significant numbers of votes in key areas of the  interior of the country.

“It’s clear the government will be left politically weaker  to face a situation made more difficult by the global economic  crisis,” he said.

Just weeks ago, Kirchner and his allies were leading the  race in Buenos Aires province, where 35 seats in the lower  house are up for grabs. Recent polls show a victory will be  slim or elusive as candidates from a dissident faction of the  Peronist party have gained ground.

If the Kirchner-led ticket is not the top vote-getter in  the key province, it will be read as a devastating loss because  it is one of the few areas of the country where he and his wife  are still fairly popular.

Since taking office in December 2007, Fernandez has  increased state intervention in the economy and financial  markets, taking over the private pension fund system and the  main airline, and has been accused of distorting key economic  data.