Islamabad: The governor and the chief minister of Punjab - Pakistan's most populous and politically significant province - appear to be on a collision course against a backdrop of simmering mutual hostility.

The row between the two political functionaries took a serious turn when Governor Salman Taseer wrote two letters to Chief Minister Shahbaz Sharif recently, criticising the latter's style of governance.

In a letter last Saturday, the governor reportedly blamed Sharif - who is also the president of Pakistan Muslim League-N (PML-N) and the younger brother of former prime minsiter Nawaz Sharif - for failing to fulfil his constitutional obligations in running the Punjab government.

Reacting to the charges levelled by the governor, Punjab Law Minister Rana Sanaullah launched a bitter tirade against Taseer, accusing him of indulging in unethical and un-Islamic activities at the Governor House in Lahore.

Rana Aftab Ahmad, the Punjab unit chief of Pakistan People's Party (PPP), a partner with PML-N in the provincial ruling coalition, took strong exception to the outburst of the provincial law minister. Ahmad said in a statement it was the constitutional right of the government to advise to the chief minister.

The PPP leadership's choice of Taseer as governor has been a bone of contention between the PPP and the PML-N.

In the parliament too, the two major parties were at loggerheads on Wednesday over a government Bill.