President Bashir was addressing a rally at his party's headquarters.
Fighting between the two countries has now spread to another area, further adding to fears of all-out war.
South Sudan seized the Heglig oil field - generally recognised as Sudanese territory - eight days ago. On Tuesday fighting broke out north of Aweil in South Sudan, about 100 miles (160km) west of Heglig.
The South Sudanese military said 22 soldiers had been killed, with casualties on both sides.
'By hook or crook'
Main disputes between the two Sudans
- Transit fees the South should pay Sudan to use its oil pipelines
- Demarcating the border
- Both sides claim Abyei
- The rights of each other's citizens now in a foreign country - there are estimated to be 500,000 southerners in Sudan and 80,000 Sudanese in the South
- Each accuses the other of supporting rebel groups on its territory
Mr Bashir said he had made a "mistake" in putting the SPLM in power in Juba.
He told the crowd that his message to the SPLM was: "Either we end up in Juba and take everything, or you end up in Khartoum and take everything."
A Sudanese foreign ministry official said Sudan would end the occupation of Heglig "by hook or crook".
A non-Sudanese source close to the border talks told the BBC that during years of discussions before its independence, South Sudan never claimed Heglig as part of its territory.
In a separate development, the world's newest country became a member of the World Bank and the International Monetary Fund on Wednesday.