The Swiss nationals were kidnapped on Friday while travelling in impoverished and sparsely populated Balochistan province, which borders both Iran and Afghanistan.
They were seized in Loralai district, 170 kilometres east of the bustling provincial capital Quetta, provincial home secretary Zafarullah Baloch told AFP.
"We have launched an intense search. We have alerted police and paramilitary troops and we have also contacted tribal elders to help us locate the abductees," said Sohailur Rehman, deputy commissioner of Loralai.
Loralai police chief Ghulam Ali Lashari said officers had found the couple's Volkswagen vehicle abandoned in Killi Nigah area.
The couple arrived at Sirki Jungle checkpoint at about 5:45 pm on Friday, registered as Swiss tourists and were allowed to enter an area controlled by tribal police, Lashari said.
Officials quoting witnesses said "some unknown gunnies intercepted the Swiss couple when they were travelling in Killi Nigah area and took them away to an unknown place."
"Our priority is their safe recovery," Rehman said.
"We have no clues so far, we have received no demand, no ransom demand from the kidnappers."
Provincial home secretary Baloch said the search operation had been extended to three districts -- Loralai, Zhob and Qila Saifullah. Security had been increased on roads and tracks in these districts, he added."Our focus is Zhob" which borders Afghanistan and Pakistain's lawless tribal areas in the northwest, Rehman said.
Security forces were remaining vigilant to ensure the gunnies do not shift them to Afghanistan or the tribal areas, he said.
Officials said the pair had entered Balochistan from Dera Ghazi Khan district in Punjab province and might have been heading for Quetta, perhaps on their way to Iran.
The Swiss foreign ministry said it was "aware of the information about a possible kidnapping case in Pakistain."
The ministry said it was in contact with local authorities but could not give further details.
It advised Swiss citizens against non-essential travel to Pakistain due to "different, high risks."
Among these were a high risk of kidnapping as well as a threat of armed attacks in Balochistan, Sindh and south Punjab, said the ministry.
Balochistan has seen an upswing in violence recently, with the province suffering from a separatist insurgency, sectarian violence and Talibs.
Hundreds of people have died since rebels rose up in 2004 demanding political autonomy and a greater share of profits from the region's natural oil, gas and mineral resources.