Attacks by insurgents in Balochistan have killed hundreds
Pakistan has warned the US that sending more soldiers to Afghanistan could endanger its southwest border region.
President Barack Obama is expected next week to order more than 30,000 extra US soldiers into Helmand province, to battle Taliban insurgents.
But Pakistan prime minister Yusuf Raza Gilani fears this would force militants over the border into Balochistan.
"We want a stable Afghanistan. At the same time we don't want our country to be destabilised," said Mr Gilani.
"This is the concern that we already discussed with the US administration - that the influx of militants towards Balochistan should be taken care of, otherwise that can destabilise Balochistan."
We have asked US to consult us in case of any paradigm shift in the policy
Yusuf Raza Gilani,
Prime minister, Pakistan
Security in Pakistan has been deteriorating ever since coalition forces entered Afghanistan eight years ago.
In Balochistan, which borders both Iran and Afghanistan, hundreds of people have died in attacks by both separatist insurgents and Taliban fighters.
In wider Pakistan, suicide attacks and bombings have killed more than 2,550 people in the last 29 months.
President Obama is due to unveil his new Afghanistan policy next week, after weeks of deliberations.
He is expected to lay out an exit strategy for withdrawing forces.
Mr Gilani said Pakistan should be consulted on any shift in America's Afghan policy, because it would be directly affected by it.
He would not say if Pakistan had been consulted on the expected troop surge.
"We have asked US administration to consult us in case of any paradigm shift in the policy... so that we can formulate our strategy accordingly," the prime minister said.
Correspondents say it is unlikely that Mr Gilani seriously believes he can influence US strategy in Afghanistan. He is more likely trying to win domestic favour.
Many Pakistanis are angry with their government's perceived support for the US military presence in Afghanistan.
Some blame the US for the suicide bombings by insurgents who have been "driven out" of Afghanistan and over the border into Pakistan.
Mr Gilani may simply be seeking to distance himself from the US announcement next week on how many new soldiers it will deploy.