Unilateral action by Turkey in Iraq could have "very grave consequences" and set a worrying precedent, Iraq's deputy prime minister has warned.
Turkey has begun preparations for a cross-border operation
Barham Saleh told the BBC such action could destabilise the region and prompt other neighbouring states to step in.
Turkey has said its patience has run out over the handling of Kurdish rebels based in northern Iraq.
It is seeking parliamentary permission for a cross-border operation to pursue Kurdistan Workers Party (PKK) members.
Ankara argues the group is a terrorist organisation responsible for the deaths of at least 15 Turkish soldiers earlier this month, and says the Kurdish separatists enjoy freedom of movement in northern Iraq.
Baghdad has called for "urgent negotiations" over Turkey's threat and has sent Iraqi Vice-President Tareq Hashemi to Ankara.
"We can understand Turkey's anger but what I'm aiming to achieve during my visit is a common understanding," Mr Hashemi said ahead of talks with Turkish leaders.
Mr Saleh warned that any cross-border operation could have destabilising effects.
Ankara says the PKK are terrorists who move freely in northern Iraq
"Any unilateral action by the Turkish military in violation of Iraqi border will be a terrible precedent for everybody," he said in the BBC interview.
"If Turkey as a neighbour of Iraq allows itself the right to intervene militarily in Iraq, what is there to prevent other neighbours from intervening?"
Meanwhile, the head of the UN refugee agency said he was deeply concerned that the Turkish action could lead to big displacements of people.
UNHCR chief Antonio Guterres said the "relatively stable" area had until now acted as a haven for Iraqis displaced from other parts of the country.
The US has also warned Ankara against ordering any incursions into Iraq.
The Turkish province of Sirnak is at the heart of the 23-year-old conflict between the military and PKK guerrillas.
Mr Erdogan's AK Party, which has a parliamentary majority, is expected to vote in favour of the motion on Wednesday.
If passed, the vote will authorise cross-border operations for one year with the government deciding on the timing, scope and frequency of any incursions.
Turkey hopes it will not be forced to resort to military action, even if its motion gained approval in parliament, Mr Erdogan said on Tuesday.
"Passage of this motion does not mean an immediate incursion will follow," he said.
Mr Erdogan called on Iraq's government and the regional administration in the country's north to crack down on the rebels, saying they should "build a thick wall between themselves and terrorist organisations".
He added that any military operation would respect Iraq's territorial integrity and only target the rebels.
Jamal Abdallah, a spokesman for the government of Iraqi Kurdistan, told the BBC there was no co-operation with the PKK.
"We have not helped the PKK and we are not helping it," he said.