New land appraisal prices in special economic zones (SEZs) for 2016-19 are set for an increase of 39% on average compared with the average rise of 28% nationwide from 2012-15.

Treasury Department director-general Chakkrit Parapuntakul said the new prices would take effect on New Year's Day next Friday.

The SEZs span six provinces, with the highest average increase in Songkhla (45.7%), which is intended as a zone for food and farm processing and a multimodal transport hub for the South and neighbouring countries.

The biggest rise in Songkhla is for a plot near Phetkasem Road that will see a 142% increase to 60,500 baht a square wah.

The second-highest average increase among the SEZ provinces is in Tak, earmarked for an international cross-docking facility and labour-intensive manufacturing.

Appraisal prices are up 42.8% in the province, with Mae Sot district tallying a 92.3% rise.

Rounding out the top five are Mukdahan (up by 38% on average), Nong Khai (33%) and Sa Kaeo (26%).

The lowest increase among SEZ provinces is in Trat, with appraisal prices up 8% on average.

The Treasury Department has finished land appraisals for 32 million plots, with prices up by 27.8% nationwide.

Bangkok's appraisal prices are up 15.8% on average.

The highest appraisal price nationwide is on Silom Road from Soi Sala Daeng to Narathiwat Road at 1 million baht per sq w, up by 17.6%.

The cheapest price nationwide is in Chiang Mai province, with land going for 10 baht per sq w.